The easiest way to figure out your undertone, is to simply look at the inside of your wrist. If you see that your veins are yellow and green, then you know that you're more of a warm tone. If you see that they're more blue, then you know that you're a cool tone. But if they're both, a combination of blue and green, then that means you're more than likely neutral. This is an easy way to figure out your undertone, so that way you can find your right shade of foundation.